GB641408A - Improvements in or relating to seal-bodies in which a conductor is sealed through a vitreous wall - Google Patents

Abstract

641,408. Quartz-to-metal seals. GENERAL ELECTRIC CO., Ltd., POWER, E. B., and NELSON, E. H. Sept. 17, 1948, No. 24447. Addition to 635,593. [Class 36] A quartz-to-metal seal of the type disclosed in the parent Specification has a conductor 1 passing through an aperture in each of two adjacent metal sheets 2, 2<SP>1</SP>, each of which is sealed on its outer side to a quartz body 4 so that there is no quartz between the sheets, and has at least one of the sheets hermetically joined to the conductor 1. The conductor, which is preferably of molybdenum or tungsten, is fitted with molybdenum discs 2, 2<SP>1</SP> which may be in contact or slightly separated, and the lower part of the conductor is wrapped in molybdenum foil 3. This assembly is inserted in a quartz tube 4 with the disc 2 abutting against the end of the tube, a pair of semicylindrical molybdenum members are placed around the projecting end of the conductor, and a second quartz tube 10 is positioned over this with the shoulder 8 abutting against disc 21. The tubes are then filled with an inert gas and the part 9 of tube 10 is sealed to the outside of tubes 4. The end of tube 10 is sealed and the assembly evacuated through the end of tube 4 which is also sealed. The quartz tubes are heated to collapse on to and embed the peripheries of discs 2, 2<SP>1</SP>. The end of tube 10 is then cut away and the semi-cylindrical members removed, leaving an annular space between the upper part of the conductor 1 and the quartz body 4. A wire of solder or brazing material is inserted in this space and the assembly heated to melt this and cause it to flow between the molybdenum discs 2, 21 to form a hermetic joint 11 on cooling. In an alternative method the peripheries of the discs 2, 21 may be left exposed so that they project through the quartz body.